Anal, oral, or vagina insertion of a cactus.
After searching for porb you saw the link to cactus porn and were intrigued by the actual meaning.
by thefatpanda March 18, 2014
Cactus porn is when a woman inserts a small cactus plant into her vagina.
"Ah, I'm just going to watch some cactus porn"
by cacty March 18, 2014